Patent DE-A-1913239 describes an air gun of the mentioned type which is characterized in that the compression chamber cylinder and the gun barrel pin-jointing and tilting fork consist of a one-piece metallic element forged by cold forming (extrusion). Moreover and according to said document said fork and said cylinder are besides connected by a midwall of reduced thickness through which a short duct is formed for the passage of the compressed air.
Patent EP-A-467819 describes on the other hand the embodiment of said barrel pin-jointing fork in plastics material, and means for its attachment to the metallic body of the compression chamber cylinder, to the effect of lowering the manufacturing cost.
For the purpose of still further reducing the manufacturing cost for said guns, patent application FR-9314267 besides describes some improvements consisting in making said compression chamber piston out of plastics material by moulding to the shape of a tubular body associated to a high density, metallic element which in its turn acts as a guide for the compression spring, an additional, wear resistant metal plate having been provided and attached to a side of said tubular body for association with the ratchet.